Heat exchangers of the above type are particularly suitable for operating with gases at high gas temperatures and under rapidly changing thermal conditions. Heretofore, these heat exchanger have been made by rigidly connecting the heat exchange tubes to the manifold ducts by soldering or welding. It is also known to form the ducts of at least two half-shells which are assembled to each other. Alternatively, the ducts can also consist of individual shorter duct sections which are arranged one after the other and soldered together.
Rigid attachment of the parts by soldering or welding has heretofore been considered necessary in order to prevent leakage during operation between the heat-exchanging fluids. This is a real problem due to application of considerable thermal stresses, particularly during non-stationary operation and because of external vibrations and vibrations caused by the flow of gas.
This construction has the disadvantage that, in the case of leaks, which can occur either due to defective manufacture or by fatigue of the material, expensive repairs or even replacement of the entire heat exchanger is frequently necessary.